Diffuser
Diffuser turns up in 2 fields: HVAC, automotive. Here is what it means to the people in each one.
Diffuser in HVAC
A supply air outlet, usually in the ceiling, that spreads air into the room in a set pattern and mixes it with room air.
Louvered square diffusers, round cones, perforated faces, linear slots and swirl diffusers each give a different pattern and throw. Good diffusers induce room air into the jet, so cold supply air is tempered before it reaches people. Picking diffusers is about cfm, throw, pressure drop and noise rating, and a wrong pick shows up as drafts, dumping or noise.
"Diffuser in the conference room is dumping cold air straight down, swap it for a slot with better throw."
Diffuser in automotive
An aerodynamic body panel at the rear of a car that increases downforce.
A shaped section of the rear underbody that smoothly transitions high-velocity airflow under the car back into the ambient atmosphere. By expanding the air as it exits, it creates a low-pressure area that effectively sucks the vehicle down onto the track. It provides significant grip at high speeds without adding the heavy aerodynamic drag associated with large rear wings.
"The customer backed into a curb and cracked the carbon fiber diffuser."